Garden and utility sheds are a useful medium for storing garden implements and as greenhouses when their sides and roofs are made up of transparent panels. They are also useful for general leisure use and are cheap and easy to erect from pre-assembled parts. They must be strong, burglar proof and weatherproof. Aesthetic qualities are also advantageous.
At present, one drawback of such sheds is that they are difficult to extend when more space is required and indeed difficult to manufacture economically for the purpose of extendibility. The difficulties stem from the fact that fully interchangeable unitary components have thus far not been manufactured which enable a shed to be extended frontwardly (i.e by removal of the front doors and addition of extra side panels) whilst maintaining standards of weatherproofing, structural integrity and security.
Frontward extendibility requires removing the front doors and adding more side-panels and roof panels frontwards without dismantling the shed. It should be noted here that a shed which provides for only rearward extension is often inconvenient for a user as the shed has usually been positioned with its rear wall against or in front of a physical boundary. If a floor is desired it too must be fully interchangeable and conform to the same connectability, weather and security requirements.
One important feature of a shed in terms of extendibility and weatherproofing is the roof structure. In order to produce an economically worthwhile roof which lends itself to forward extendibility whilst maintaining standards of weatherproofing, structural-integrity, theft-proofing and non-extendible roof quality, it must be manufactured to interlock with existing roof panels and wall panels in a fully interchangeable fashion. Thus, a roof panel should equally be able to cover the section above the front doors, the section above the rear wall and a middle section, whilst maintaining standards of weatherproofing, structural integrity, theftproofing and non-interchangeable roof quality. Non interchangeable roof quality usually consists of a single blow-moulded roof structure which is closed on three sides, having closed surfaces in three dimensions thus leaving no gap between the sides and the roof. This gives aesthetic and weatherproofing qualities, amongst other things, with no gap between the sides and the roof.
Further, ensuring the surface of an extendible roof is weatherproof is a difficult task as the requirement of dismantlability may affect the weatherproofing.
Further, the roof must contain protrusions at right angles to the roof surface in order to connect with the walls of the shed. The dual requirements of interlockability with adjacent roof panels which stems from the extendibility requirement and ability to lock to a wall panel coupled with the non-interchangeable roof quality requirement require a structure which is "closed on three sides" (as blow moulded non-interchangeable roof) as in a blow-moulded non-extendible roof structure. Being closed on three sides means the structure may fulfil all the above requirements whilst being manufactured as a unitary item. Hitherto, such a component has not been manufactured in a unitary fashion.
Reference is now made to FIG. 1 which shows an example of a prior art modular wooden shed, generally referenced 10, sold by the marketing chain: Castorama Diffusion S. A., Rue Du Chemin Vert, Lesquin, Cedex 120481, France. There does not currently exist a forwardly extendible shed currently manufactured, the "Castorama" shed reaching nearest to this goal.
The shed consists of side walls 12, roof sections 14 and a front wall 16, containing a door 18. It is purchased with as many extra side and roof panels 12A and 14A required for a chosen size. The "Castorama" is the modular in a limited way as not all the parts are interchangeable. It is certainly not extendible as dismantling would be required even if extension were feasible. Further, the shed would only be rearwardly extendible if extension were at all possible after it was built.
It is no surprise that the shed is manufactured from wood and this illustrates the difficulties associated with manufacturing the required roof and wall components in a unitary fashion from plastic.
Referring now to FIGS. 2A-2B there is shown an illustration of a prior art non-extendible shed with a roof displaying the qualities, referred to hereinabove, of a hitherto non-extendible roof (FIG. 2A). It can be seen that the roof 19 is of a "hat-like" construction (FIG. 2A) closed on three sides or dimensions A, B and C illustrated in FIG. 2B. Such a construction is obtained by blow-molding the plastic roof as is known in the art, so that roof 19 has the appearance of a wood panel.
There are many similar (non-extendible) sheds sold, not all having a blow molded roof, none of which are extendible. Examples of manufacturers of these include: Rubbermaid Incorporated, 1147 Akron Road, Wooster, Ohio, U.S.A; Royal Outdoor Vinyl Products and Royal Outdoor Products Inc. both members of Royal Group Technologies Ltd, 200 Hanlan Road, Woodbridge, Ontario, Canada.
Blow molding is ineffective for similar quality extendible roofs as weatherproofing and interconnectability are hard to achieve in a unitary blow-molded process-produced roof whilst maintaining weatherproofing, connectability and economic advantage.